Multifunctional microelectronics fibers as implantable bioelectronic interfaces

Abstract

Multifunctional microelectronics fiber probes can be chronically implanted in tissue of awake-behaving animals for understanding brain-viscera communication. These fiber probes can be made using thermal drawing to make hundreds of meters of flexible fiber that incorporates features such as light sources, electrodes, thermal sensors, and microfluidic channels in a multilayered configuration. The fiber mechanics can be tuned for two distinct device layouts: (1) higher-modulus, flexible brain fibers for implantation into deep-brain; and (2) soft, compliant gut fibers for implantation into the small intestine. Brain fibers can modulate the deep-brain mesolimbic reward pathway. Gut fibers can perform peripheral optogenetic stimulation of vagal afferents from the intestine to stimulate brain reward neurons. Brain and gut fibers can be connected to a control module, for example, with a coiled, stretchable interconnect that is more flexible and stretches more than even soft gut fibers, in dual-organ (gut-brain) implantation.

1 . A multifunctional fiber probe comprising:
 a polymer fiber segment having (i) a proximal end and (ii) a distal end configured to be inserted into tissue;   a microfluidic channel running along a length of the polymer fiber segment and having a first opening at the proximal end of the polymer fiber segment and a second opening at the distal end of the polymer fiber segment and configured to convey fluid between the first opening and the second opening;   electrodes running along the length of the polymer fiber segment and configured to make electrophysiology measurements of the tissue;   electrical interconnects running along the length of the polymer fiber segment;   solid-state devices disposed along the length of the polymer fiber segment or disposed along a distal portion of the polymer fiber segment in electrical communication with the electrical interconnects and configured to interact with the tissue; and   a control module at a proximal end of the polymer fiber segment and connected to the electrical interconnects and the electrodes and configured to record the electrophysiology measurements and to control the solid-state devices.   
     
     
         2 . The multifunctional fiber probe of  claim 1 , wherein the polymer fiber segment comprises at least one of polycarbonate (PC) or styrene-ethylene-butylene-styrene (SEBS). 
     
     
         3 . The multifunctional fiber probe of  claim 1 , wherein the polymer fiber segment has a Young's modulus of about 2.3 GPa to about 3.0 GPa. 
     
     
         4 . The multifunctional fiber probe of  claim 1 , wherein the polymer fiber segment has a Young's modulus of about 5 MPa to about 30 MPa. 
     
     
         5 . The multifunctional fiber probe of  claim 1 , wherein the solid-state devices comprise light-emitting diodes configured to optogenetically modulate tissue with pulses of green light and/or blue light. 
     
     
         6 . The multifunctional fiber probe of  claim 1 , wherein the solid-state devices comprise temperature sensors configured to measure a temperature of the tissue around the distal portion of the polymer fiber segment. 
     
     
         7 . The multifunctional fiber probe of  claim 1 , wherein the control module comprises a wireless transceiver configured to receive commands from an external device and/or to transmit data to the external device. 
     
     
         8 . The multifunctional fiber probe of  claim 1 , further comprising:
 a stretchable interconnect connecting the proximal end of the polymer fiber segment to the control module.   
     
     
         9 . The multifunctional fiber probe of  claim 8 , wherein the stretchable interconnect comprises a helically coiled fiber with embedded microwires in electrical communication with the electrical interconnects and the control module. 
     
     
         10 . The multifunctional fiber probe of  claim 8 , wherein the polymer fiber segment and at least a part of stretchable interconnect are configured to be implanted in the tissue. 
     
     
         11 . The multifunctional fiber probe of  claim 8 , wherein the polymer fiber segment is a first polymer fiber segment, the electrical interconnects are first electrical interconnects, and the tissue is brain tissue, and further comprising:
 a second polymer fiber segment configured to be inserted into gastrointestinal tissue;   second electrical interconnects running along a length of the second polymer fiber segment, and   wherein the control module is operably coupled to the second electrical interconnects.   
     
     
         12 - 20 . (canceled)